A 7-year-old girl with a history of a VP shunt presents with a headache for 2 days and worsening fever. The patient’s mother states that the child had a shunt placed during her first year of life for congenital aqueductal stenosis. The patient is febrile in the ED, with a temperature of 38.6°C, but is nontoxic. Her other vital signs are: heart rate, 118 beats/min; respiratory rate, 20 breaths/min; blood pressure 98/62 mm Hg; and oxygen saturation, 100% on room air. Her physical examination is unremarkable except for a mildly erythematous throat. What are important points on your history that should be elicited for a patient with a VP shunt and fever? If you are concerned about a VP shunt infection, what laboratory studies should be ordered? Do you need to order any imaging studies to look for a possible shunt malfunction? Should you call this child’s neurosurgeon?
A 3-year-old girl with a VP shunt, who is suffering from altered consciousness and persistent vomiting, is brought to your community ED via EMS. The patient’s mother states the child has been drowsy for the past few weeks. Upon arrival, you place the girl on a monitor and a nonrebreather mask and obtain the following vital signs: heart rate, 76 beats/min; respiratory rate, 20 breaths/min; blood pressure, 110/65 mm Hg; and oxygen saturation, 100% on the nonrebreather. Upon primary survey, the patient’s airway is intact, but there are coarse breath sounds bilaterally over her chest. Her capillary refill is < 2 seconds. Her GCS score is 9, and you note that one pupil seems to be more dilated than the other and appears to be sluggishly reactive. The patient is not responding to your commands. What could be causing this patient’s symptoms? Without a neurosurgeon in-house, what should your management of this patient be? Does the patient need imaging prior to any procedures?
A 5-year-old boy with a history of constipation, mild developmental delay, and a VP shunt presents with 1 week of vomiting. His mother states he is chronically on stool softeners. For the past week, the patient has had 2 to 3 episodes of nonbloody, nonbilious vomiting per day. He has not had diarrhea, but his last stool, which was earlier today, was watery. The mother states he has not been complaining of headaches, but has been eating and drinking less. His vital signs are stable upon arrival. The patient’s examination is normal, including the neurologic examination, except for mild periumbilical tenderness. There is no rebound or guarding upon abdominal palpation. You realize that this could be a typical presentation of constipation, but the patient’s VP shunt makes you consider possible shunt complications. You begin to wonder if this could possibly be a shunt obstruction or infection. What steps should be taken in the management of this patient? What history is important in this case? What physical examination findings might help with the diagnosis?
Ventriculoperitoneal (VP) shunts are the treatment of choice for patients with hydrocephalus, an excessive accumulation of cerebrospinal fluid (CSF) within the brain caused by an imbalance between CSF production, flow, or absorption. Most commonly, pressure builds up proximal to an obstruction, leading to ventricular dilatation and raised intracranial pressure (ICP).1 (See Figure 1). The pathophysiology of hydrocephalus has been known since the 1800s, but effective treatment was not available until the 1950s, when John Holter developed a shunt to allow drainage of excess CSF, in an attempt to treat his own son, who was suffering from hydrocephalus.2 Since then, the standard treatment of hydrocephalus has been the insertion of a ventricular shunt, and it has dramatically reduced the morbidity and mortality of hydrocephalus.3,4
A shunt consists of 4 major components: a proximal catheter, a 1-way valve, a reservoir, and a distal catheter.5 (See Figure 2.) Most neurosurgeons place shunts that contain medium-pressure valves and drain CSF continuously when the pressure in the ventricles is > 10 mm Hg.6 The proximal catheter is normally inserted in the parieto-occipital region of the lateral ventricle, and the 1-way valve and reservoir run behind the ipsilateral ear. The distal portion of the catheter is tunneled down through the neck and chest wall and, most commonly, ends in the peritoneal cavity.3,5 Other areas where the catheter can terminate include the pleural cavity, atrium, and gallbladder; however, the peritoneal cavity is the preferred site of termination, as it is associated with the fewest complications.7 If placed in infancy or childhood, the distal catheter has extra length in the abdomen to allow for growth of the patient. Many newer valves allow for the opening pressure to be adjusted externally via a magnetic or electromagnetic device; these “programmable" shunts obviate the need for surgery to change the pressure setting.1
Unfortunately, VP shunts are not long-lasting, and revision may be required 1 to 2 times every 10 years.3 The Pediatric Shunt Design Trial was a randomized controlled trial that compared differ-ent types of shunts in patients with hydrocephalus. According to this prospective study, approximately one-third of shunts require revision in the first postoperative year and > 50% fail by the second year after insertion.8 This study, as well as others, found failure to be independent of valve type.1,7,8 There are several risk factors for complications, including: younger age, history of prematurity, number of revisions, and shorter time from insertion to first revision.4,9-11 Ethnicity also has been linked to shunt complications. Specifically, blacks, Hispanics, and Native Americans have a higher rate of complications compared to Asians and whites.4,12,13 The number of shunt placements is increasing each year. The annual malfunction rate is projected to be as high as 5%.5,14 The mortality rate from a shunt malfunction can be as high as 1% to 2%.15
Both the history and physical examination are very important when evaluating a patient with a possible shunt complication, and will guide the emergency clinician in making management decisions. This issue will help practitioners identify possible shunt complications, determine necessary diagnostic and management steps, and decide appropriate dispositions.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study are included in bold type following the references, where available. The most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.
Jacqueline Bober, DO, FAAP; Johnathan Rochlin, MD; Shashidhar Marneni, MD
February 2, 2016
March 2, 2019
Upon completion of this article, you should be able to:
Physician CME Information
Date of Original Release: February 2, 2016. Date of most recent review: January 15, 2016. Termination date: January 2, 2019.
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